This invention relates to lasers and, more particularly, to lasers used to amplify optical signals.
Optical fiber amplifiers are often used in optical fiber systems to prevent data from being attenuated while traveling through an optical fiber system. Data attenuation between transmitter and receiver is a problem in optical fiber systems. This is because, if the data is attenuated during its travel from the transmission end to the receiving end, when the data arrives at the receiving end the data may not be readable.
To address the above problem, optical fiber systems make use of optical fiber amplifiers that add energy to the signal via a pump laser. However, optical fiber amplifiers require a large input power, in excess of several watts, and must be reliable over a long period of time. As a result, creating a reliable pumping source that also has high power has proven difficult.
The use of multiple pump lasers that have a suitable collective power has also been tried. Although such multiple pump lasers exist, they only use a maximum of four discrete lasers. With a small number of lasers, a failure of one or more lasers substantially affects the output power, thereby reducing reliability. Good pump lasers are also highly temperature sensitive, so there is a high cost associated with maintaining a pump laser within a narrow temperature band. Thus, there is a need for a way to create a cheap reliable pumping laser.
In accordance with the invention, creation of a pump laser that does not suffer from the problems of the prior art is made possible.
One aspect of the invention involves a pump laser capable of delivering at least a specified amount of output power. The pump laser has an array of N semiconductor lasers, each having a first wavelength and an individual available output power (P). The individual available output power is such that the product of N times P is equal to or greater than the specified amount of output power. The pump laser also has a coupler configured to couple light emitted by the individual lasers in the array to an individual optical fiber.
The advantages and features described herein are a few of the many advantages and features available from representative embodiments and are presented only to assist in understanding the invention. It should be understood that they are not to be considered limitations on the invention as defined by the claims, or limitations on equivalents to the claims. For instance, some of these advantages are mutually contradictory, in that they cannot be simultaneously present in a single embodiment. Similarly, some advantages are applicable to one aspect of the invention, and inapplicable to others. Thus, this summary of features and advantages should not be considered dispositive in determining equivalence. Additional features and advantages of the invention will become apparent in the following description, from the drawings, and from the claims.